Accuracy fixed.

[dreadpirate]

Because if there is any chance that this blue loctite will become liquefied and run back into the receiver area I think that I might pass on using Loctite. But I still like the idea of using the tool to square up the face of the receiver and filling in the gap (if necessary) between the outside of the extension and inside of the receiver. These two ideas seem like they are relatively cheap and easy to help,or possibly solve accuracy problems. Or inaccuracy? (IMO)

Ok - Loctite or not - if you guys think your AR is heating up to 450 deg F, now you have to worry about annealing the aluminum upper. I really, really doubt it's going to get that hot.